When upgrading windows in historic buildings in Lithuania, professionals often face a critical decision: slim double glazing or vacuum glazing? While both are technically acceptable under heritage guidelines, they’re not created equal.
Slim double glazing has been around longer and is widely known. However, vacuum glazing—especially from advanced manufacturers like LandVac—offers a step-change in both performance and design. It’s time to move beyond “acceptable” and aim for what’s best.
In heritage projects, appearance is everything. Preserving the original charm of windows is vital.
Slim Double Glazing: Although thinner than standard units, slim double glazing still has a noticeable profile. It may introduce double reflections, disrupting the clean, authentic look of original windows.
Vacuum Glazing: With a thickness of just 8.3 mm, vacuum glazing closely mimics single glazing. It eliminates double reflections and integrates seamlessly into traditional frames.
✅ Verdict: Vacuum glazing preserves historical authenticity far better than slim double glazing.
When investing in glazing for a historic property, long-term performance matters.
Slim Double Glazing: Typically comes with a 7–10 year warranty, but is vulnerable to seal failures, leading to fogging and reduced insulation.
Vacuum Glazing: Offers a 15-year warranty with a lifespan of up to 25 years. Its vacuum-sealed construction significantly reduces the risk of misting and failure.
✅ Verdict: Vacuum glazing is more durable and offers a lower risk of long-term issues.
Energy efficiency and comfort are key selling points for any upgrade.
Slim Double Glazing: Provides U-values between 1.3–2.2 W/m²K and basic noise reduction—adequate but not impressive.
Vacuum Glazing: Delivers industry-leading U-values down to 0.4 W/m²K, with sound insulation up to 39dB. Perfect for urban or noisy environments.
✅ Verdict: Vacuum glazing far exceeds slim double glazing in insulation performance.
Installing new glazing shouldn’t compromise the original structure.
Slim Double Glazing: Heavier weight can stress traditional sash or casement frames, requiring reinforcement or alterations.
Vacuum Glazing: Its lightweight and thin profile allow for easier integration into original frames, preserving architectural details.
✅ Verdict: Vacuum glazing is more frame-friendly, especially for delicate historic windows.
Planning approval is essential when working on protected properties.
Slim Double Glazing: Familiar, but its bulk can raise concerns in sensitive conservation areas.
Vacuum Glazing: Increasingly approved by conservation officers thanks to its near-invisible profile and high performance.
✅ Verdict: Once introduced to vacuum glazing, most officials see it as the superior option.
Slim double glazing served its role during a transitional period in heritage window upgrades. But today’s standards demand better. Vacuum glazing delivers:
✅ Higher thermal and acoustic insulation
✅ Authentic appearance similar to single glazing
✅ Better compatibility with original frames
✅ Easier approval from heritage authorities
Whether you're refurbishing sash windows in Vilnius or replacing casements in Kaunas, vacuum glazing offers a future-proof solution that honours the past while embracing performance.
👉 Contact Vacuum Glazing UK today to explore LandVac solutions tailored for historic buildings in Lithuania.
Get a quote or speak with a Lithuanian distributor to start your next heritage project the right way.
Skaitykite šį įrašą lietuvių kalba.